1. Field of the Invention
This invention relates micro-miniature x-ray apparatus in general and, more particularly, to such apparatuses in which the direction of an x-ray beam can be focused and steered.
2. Discussion of the Related Art
Several workers in the medical equipment field have proposed miniature x-ray sources for the treatment of maladies such as cancer tumors and coronary artery disease. In general, the source is inserted into body vessels or other body cavities in order to reach and irradiate the diseased area. In one approach, a catheter with a miniature x-ray source is contemplated for irradiation of cardiovascular tissue. For the treatment of a stenosed artery such a catheter has been proposed for use in conjunction with Percutaneous Transluminal Coronary Angeoplasty (PCTA). See, for example, C. Ribbing et al., U.S. Pat. No. 6,477,233 issued on Nov. 5, 2002 and R. Shefer et al., U.S. Pat. No. 6,148,061 issued on Nov. 14, 2000, both of which are incorporated herein by reference.
Both of these patents, however, describe x-ray sources that emit x-rays isotropically. The output of the sources is not focused and is not steered, which is undesirable to the extent that healthy tissue in the vicinity of the diseased area is irradiated with x-rays.
Thus, a need remains in the art for a miniature x-ray source whose output can be focused and steered.
A need also remains for a miniature x-ray source that can be implemented using a multiplicity of wafer or chip assemblies.